Olympic Torch Tech: How Flame Survives Weather & Worse
for National Geographic News
|April 9, 2008|
|This year the Olympic torch is undergoing unprecedented abuse, from protesters jostling over it to howling winds atop Mount Everest to potential relay cancellations.|
But the 2008 torch can take the heat.
Decades of innovation have made the torch the height of combustion technology—all in service to the ultimate flame imperative: The fire lighted at ancient Olympia in Greece on March 24 must be the same flame that lights the Olympic cauldron in Beijing on August 8.
(See photos illustrating how the Olympic torch has changed throughout history.)
According to Chinese press and the Beijing Olympics Web site, this year's torch boasts a flame that can withstand winds of up to 40 miles an hour (65 kilometers an hour), nearly 2 inches (5 centimeters) of rain an hour, and temperatures of minus 40 degrees Fahrenheit (-40 degrees Celsius).
The flame is fueled entirely by propane, which marks a departure from its predecessors.
The 2000 Sydney Olympics' torch burned a propane-butane mix. Athens's torch was run on propylene and butane, which produced a bit more soot but increased the flame's brightness—important for those daytime photo ops.
The state-owned China Aerospace Science and Industry Corporation designed the new torch's burning system—and it is, in a sense, rocket science.
Comparing modern Olympic torch technology and rocket design, engineer Richard Kelso said: "Both areas are very complex. And they require knowledge of combustion, fluid mechanics, thermodynamics, aerodynamics, materials science, and also manufacturing."
Kelso, of the University of Adelaide in Australia, was chief design coordinator of the 2000 Sydney Olympic torch's fuel-and-combustion system as well as a senior design engineer for the 2004 Athens torch.
"If [the 2008 torch's fuel] truly is propane then I would expect that the flame wouldn't be quite as bright as Athens and Sydney," Kelso said.
For the Olympic flame's first underwater relay in 2000, at the Great Barrier Reef, designers created a special solid-fuel torch that worked like a distress flare.
The Chinese may also have had to adapt their torch to extreme environments, including Mount Everest. But at least their fuel won't freeze.
American Chemical Society senior scientist Jerry Bell said: "Even if it's cold, propane is going to vaporize. And I'm pretty sure that's what they're going to do when they go up Everest."
Bell is confident that Everest's air isn't so thin that it will snuff out the flame.
Fourteen Thousand Torches
Comprehensive details on this year's torch's inner workings are elusive so far.
"I don't know why it should be a secret," Bell said. "It can't be that complicated, and it can't be vastly different than it's been in the past."
About a decade ago torches were equipped with pilot lights that relit the larger, more photogenic flame when it blew out.
"Pretty much the guts have been designed in a similar way ever since," Bell said.
Ever since Atlanta 1996 each runner is also given a fresh new torch to burn through, as opposed to reusable torches or replaceable fuel canisters.
"We talk about the Olympic torch. But there are thousands of them, because they only last for 20 minutes or so," Bell said.
The Sydney and Athens games each manufactured about 14,000 torches for their respective relays.
In his experience in the last two Summer Olympics, Kelso said, sudden gusts of wind and mishandling by relay runners caused the most flameouts.
This year the most common causes of extinguished torches could be anti-Chinese-government protesters. On Tuesday officials in Paris put out the torch three times due to interruptions by activists.
But not to fear, backup flames are near—all derived from the flame used to light the first 2008 torch at ancient Olympia in Greece.
"They hedge their bets and distribute [flames] to different places. So if they lose the torch flame completely, they can relight it," Kelso said.
The "insurance" flames are kept lit in miners' lanterns—at least one of which travels with the relay at all times.
If the flame has to fly, it travels in these lanterns, which keep it contained and therefore comply with no-open-flame rules for airplanes.
"It's an enormously complicated logistical nightmare," Kelso said of the torch relay, which this year will involve an unprecedented number of participants.
But no matter how large the relay gets, or how exotic its route becomes, the flame at the start is the flame you get burning in the Olympic cauldron at the end, Kelso said.
"[Organizers] are very, very careful about maintaining the integrity of the flame."
|© 1996-2008 National Geographic Society. All rights reserved.|